For the best deal on long-term rentals, book in advance from home.
If you decide to rent a car while in Europe, try calling around to local car-rental agencies, or book through a local travel agency.
When renting a car, you’ll need to make a few decisions, including whom to rent from, what kind of car to get, and where to pick it up and drop it off.
Which Rental Company?
These days, most of us start our search on a travel-booking site such as Kayak, Expedia, or AAA.
Of course, if you have a favorite car-rental agency at home, consider using the same company in Europe.
When shopping around, don’t stop at just comparing initial price quotes.
You’ll want to determine which company’s offer involves the best combination of rates (including all fees and any extras you want), service, and pickup/drop-off locations (with workable office hours) for your trip.
Even with the wealth of information that’s available online, you may find that it’s easier to make a phone call to get all your questions answered.
It’s generally an advantage to go with a larger company, with a wider choice of pickup and drop-off locations.
Most of the big-time US rental agencies have offices throughout Europe, as do the two major Europe-based agencies, Europcar and Sixt.
With these companies, if you get into car trouble, a replacement car is likely to be close at hand.
Still, it’s smart to make sure you choose a company that thoroughly covers the areas where you’ll be driving.
It’s also worth considering renting through a consolidator, such as Auto Europe (my favorite) or Europe by Car.
These companies compare rates among various companies (including many of the big-name firms), find the best deal, and — because they’re wholesalers — pass the savings on to you.
You pay the consolidator, and they issue you a voucher to pick up your car in Europe.
With a consolidator as a middleman, it’s especially important to ask ahead of time about add-on fees and restrictions, since you might not learn this critical information until you pick up the car.
If any dispute arises when you show up at the rental desk, call the consolidator to try to resolve the issue — ask to use the rental office’s phone (the consolidator’s number is toll-free from any land line).
Once you sign off on something with the vendor, it’s difficult for the consolidator (or anyone else) to reverse what you’ve agreed to.
If you have a problem with the rental agency, the consolidator may not be able to intervene to your satisfaction, but at least you’ll have gotten some help in resolving the problem.
No matter whom you rent through, be sure to hang onto all your paperwork (including the checklist used by the company to check the car’s condition when you turn it in) for a few months after the rental period, in case a billing dispute arises.
Source: Tips for Booking a Rental Car